The effect of texture on the serrated flow in peak-aged 2090 Al-Li alloy

Tensile specimens cut from the surface layer to the center layer of a 12.7 mm thick 2090 Al-Li alloy plate were solution treated at 550 degrees C for 30 min and subsequently peak-aged at 190 degrees C for 18 h. They were tensile tested along the rolling direction at 25 degrees C at various strain rates. The solution-treated specimens gave rise to serrated flows at a strain rate of 2x 10(4) s(-1). On the other hand, for the peak-aged alloy, the surface-layer and subsurface-layer specimens underwent complex, serrated flows (fine and coarse types superimposed each other), whereas the center-layer and near-center-layer specimens were devoid of serrated flows. The textures of the surface-layer and sub surface-layer specimens were approximated by the {001}< 110 > orientation, while those of the center-layer and near-center- layer specimens were approximated by the {011}< 211 > orientation. The different flow behaviors were discussed based on the crystallographic textures, microstructures and the strain rates.